1) Field of the Invention
The present invention relates to a method of setting a sub-scanning beam pitch of a multibeam light source for an information recording apparatus such as a laser printer, a digital copier, and a facsimile.
2) Description of the Related Art
Recently, a high speed recording with a high recording density is required for an information recording apparatus such as a laser printer and a digital copier. To meet the requirement, a multibeam scanner is widely used, which simultaneously scans a recording medium, such as a photo conductor, with a plurality of laser beams.
Some of light sources having a plurality of laser beams use a semiconductor laser array in which a plurality of semiconductor lasers are arranged in an array on the same substrate. The light sources are disclosed, for example, in Japanese Patent Application Laid Open No. 56-42248, 9-26550, and 8-136841.
Conventionally, an interval between emission points in the semiconductor laser array is 100 xcexcm or more to avoid a cross interference between lasers. Recently, however, a semiconductor laser array in which the interval between emission points is 20 xcexcm or less is available because of improved isolation technology and semiconductor fabrication technology.
On the other hand, some of the light sources have a function of correcting a plurality of laser beams in order to improve resolution and image quality. Such light sources are disclosed, for example, in Japanese Patent Application Laid-Open Publication No. 9-251137, 9-211350, 9-1861, and Japanese Patent No. 2727198.
However, the technology described in Japanese Patent Application Laid-Open Publication No. 9-251137 requires a complex sensor and a complicated beam detection algorithm, and the technology described in Japanese Patent Application Laid-Open Publication No. 9-211350 and 9-1861 requires a correction of a write-out position.
In Japanese Patent No. 2727198, a method of performing a beam-scanning is disclosed. This method includes correcting positions of laser beams so as to arrange the laser beams deviated in a main scanning direction on the same position to perform the beam-scanning. However, Japanese Patent No. 2727198 does not describe a so-called multibeam light source that simultaneously uses the laser beams for scanning. Furthermore, a pitch error caused by a plane tilt error of a deflecting reflector is not taken into account.
It is an object of the present invention to solve at least the problems in the conventional technology.
The multibeam light source according to one aspect of the present invention includes a plurality of semiconductor laser arrays, wherein each semiconductor laser array includes a plurality of semiconductor lasers each of which emits a laser beam, and a deflector that receives the laser beams and deflects the laser beams towards a recording medium, whereby an array of focuses is formed on the recording medium corresponding to each semiconductor laser array, wherein a sub-scanning beam pitch is set as Pxe2x88x92(A/VM)xc2x7VS+C, where P is a recording density interval on the recoding medium, VM is a main scanning velocity, VS is a sub-scanning velocity, A is an interval between the arrays of focuses in a main scanning direction, and C is a correction amount of the beam pitch, wherein the sub-scanning beam pitch is defined by a distance between an arbitrary point on a line connecting focuses of a preceding array of the focuses and a point that corresponds to the arbitrary point on a line connecting focuses of an adjoining array of the focuses.
The multibeam light source according to another aspect of the present invention includes a plurality of semiconductor laser arrays, wherein each semiconductor laser array includes a plurality of semiconductor lasers each of which emits a laser beam, and a deflector that receives the laser beams and deflects the laser beams towards a recording medium, whereby an array of focuses is formed on the recording medium corresponding to each semiconductor laser array, wherein a sub-scanning beam pitch is set as Pxe2x88x92(A/VM)xc2x7VS+C, where P is a recording density interval on the recoding medium, VM is a main scanning velocity, VS is a sub-scanning velocity, A is an interval between the arrays of focuses in a main scanning direction, and C is a correction amount of the beam pitch, wherein the sub-scanning beam pitch is defined by a distance between a most preceding array of the focuses and an adjoining array of the focuses.
The multibeam light source according to still another aspect of the present invention includes a plurality of semiconductor laser arrays, wherein each semiconductor laser array includes a plurality of semiconductor lasers each of which emits a laser beam, and a deflector that receives the laser beams and deflects the laser beams towards a recording medium, whereby an array of focuses is formed on the recording medium corresponding to each semiconductor laser array, wherein a sub-scanning beam pitch is set as Pxe2x88x92(A/VM)xc2x7VS+C, where P is a recording density interval on the recoding medium, VM is a main scanning velocity, VS is a sub-scanning velocity, A is an interval between the arrays of focuses in a main scanning direction, and C is a correction amount of the beam pitch, wherein the sub-scanning beam pitch is defined by a distance between a center of focuses of a first semiconductor laser array and a center of focuses of a second semiconductor laser array, wherein the first semiconductor laser array scans first in a main scanning direction and the second semiconductor laser array scans next in the main scanning direction.
The multibeam scanner according to still another aspect of the present invention includes a multibeam light source having a plurality of semiconductor laser arrays, wherein each semiconductor laser array includes a plurality of semiconductor lasers each of which emits a laser beam, and a deflector that receives the laser beams and deflects the laser beams towards a recording medium, whereby an array of focuses is formed on the recording medium corresponding to each semiconductor laser array, wherein a sub-scanning beam pitch is set as Pxe2x88x92(A/VM)xc2x7VS+C, where P is a recording density interval on the recoding medium, VM is a main scanning velocity, VS is a sub-scanning velocity, A is an interval between the arrays of focuses in a main scanning direction, and C is a correction amount of the beam pitch, wherein the sub-scanning beam pitch is defined by a distance between an arbitrary point on a line connecting focuses of a preceding array of the focuses and a point that corresponds to the arbitrary point on a line connecting focuses of an adjoining array of the focuses.
The multibeam scanner according to still another aspect of the present invention includes a multibeam light source having a plurality of semiconductor laser arrays, wherein each semiconductor laser array includes a plurality of semiconductor lasers each of which emits a laser beam, and a deflector that receives the laser beams and deflects the laser beams towards a recording medium, whereby an array of focuses is formed on the recording medium corresponding to each semiconductor laser array, wherein a sub-scanning beam pitch is set as Pxe2x88x92(A/VM)xc2x7VS+C, where P is a recording density interval on the recoding medium, VM is a main scanning velocity, VS is a sub-scanning velocity, A is an interval between the arrays of focuses in a main scanning direction, and C is a correction amount of the beam pitch, wherein the sub-scanning beam pitch is defined by a distance between a most preceding array of the focuses and an adjoining array of the focuses.
The multibeam scanner according to still another aspect of the present invention includes a multibeam light source having a plurality of semiconductor laser arrays, wherein each semiconductor laser array includes a plurality of semiconductor lasers each of which emits a laser beam, and a deflector that receives the laser beams and deflects the laser beams towards a recording medium, whereby an array of focuses is formed on the recording medium corresponding to each semiconductor laser array, wherein a sub-scanning beam pitch is set as Pxe2x88x92(A/VM)xc2x7VS+C, where P is a recording density interval on the recoding medium, VM is a main scanning velocity, VS is a sub-scanning velocity, A is an interval between the arrays of focuses in a main scanning direction, and C is a correction amount of the beam pitch, wherein the sub-scanning beam pitch is defined by a distance between a center of focuses of a first semiconductor laser array and a center of focuses of a second semiconductor laser array, wherein the first semiconductor laser array scans first in a main scanning direction and the second semiconductor laser array scans next in the main scanning direction.
The method of scanning according to still another aspect of the present invention includes setting a sub-scanning beam pitch as Pxe2x88x92(A/VM)xc2x7VS+C, where P is a recording density interval on the recoding medium, VM is a main scanning velocity, VS is a sub-scanning velocity, A is an interval between the arrays of focuses in a main scanning direction, and C is a correction amount of the beam pitch, wherein the sub-scanning beam pitch is defined by a distance between an arbitrary point on a line connecting focuses of a preceding array of the focuses and a point that corresponds to the arbitrary point on a line connecting focuses of an adjoining array of the focuses, wherein the method of scanning is used on a multibeam scanner including a plurality of semiconductor laser arrays, wherein each semiconductor laser array includes a plurality of semiconductor lasers each of which emits a laser beam, and a deflector that receives the laser beams and deflects the laser beams towards a recording medium, whereby an array of focuses is formed on the recording medium corresponding to each semiconductor laser array.
The method of scanning according to still another aspect of the present invention includes setting a sub-scanning beam pitch as Pxe2x88x92(A/VM)xc2x7VS+C, where P is a recording density interval on the recoding medium, VM is a main scanning velocity, VS is a sub-scanning velocity, A is an interval between the arrays of focuses in a main scanning direction, and C is a correction amount of the beam pitch, wherein the sub-scanning beam pitch is defined by a distance between a most preceding array of the focuses and an adjoining array of the focuses, wherein the sub-scanning beam pitch is defined by a distance between an arbitrary point on a line connecting focuses of a preceding array of the focuses and a point that corresponds to the arbitrary point on a line connecting focuses of an adjoining array of the focuses, wherein the method of scanning is used on a multibeam scanner including a plurality of semiconductor laser arrays, wherein each semiconductor laser array includes a plurality of semiconductor lasers each of which emits a laser beam, and a deflector that receives the laser beams and deflects the laser beams towards a recording medium, whereby an array of focuses is formed on the recording medium corresponding to each semiconductor laser array.
The method of scanning according to still another aspect of the present invention includes setting a sub-scanning beam pitch as Pxe2x88x92(A/VM)xc2x7VS+C, where P is a recording density interval on the recoding medium, VM is a main scanning velocity, VS is a sub-scanning velocity, A is an interval between the arrays of focuses in a main scanning direction, and C is a correction amount of the beam pitch, wherein the sub-scanning beam pitch is defined by a distance between a center of focuses of a first semiconductor laser array and a center of focuses of a second semiconductor laser array, wherein the first semiconductor laser array scans first in a main scanning direction and the second semiconductor laser array scans next in the main scanning direction, wherein the method of scanning is used on a multibeam scanner including a plurality of semiconductor laser arrays, wherein each semiconductor laser array includes a plurality of semiconductor lasers each of which emits a laser beam, and a deflector that receives the laser beams and deflects the laser beams towards a recording medium, whereby an array of focuses is formed on the recording medium corresponding to each semiconductor laser array.
The other objects, features and advantages of the present invention are specifically set forth in or will become apparent from the following detailed descriptions of the invention when read in conjunction with the accompanying drawings.